RT8800A的特性及应用

General Purpose 3-Phase PWM Controller for High-Density Power Supply

The RT8800A is a general-purposed mulTI-phase synchronous buck controller dedicaTIng for high power density applicaTIons. The RT8800A operates with 2 or 3 synchronous buck switching stages in interleaved phase set automaTIcally. The multiphase architecture provides high output current while maintaining low power dissipation on power devices and low stress on input and output capacitors.
The output voltage is precisely regulated to the external reference voltage at PI pin. The RT8800A can provide Intel® VRD10.x or AMD® K8 compliant output voltage when companioned with DAC generator RT9401A/B.

The RT8800A adopts innovative time-sharing DCR current sensing technique for channel current balance, droop tuning, and over current protection. Using one common GM amplifier for current sensing eliminates offset errors and linearity variation between GMs. As sub-milli-ohm-grade inductors are widely used in modern mother boards, slight mismatch of GM amplifiers offset and linearity results in considerable current shift between phases. The time-sharing DCR current sensing technique is extremely important to guarantee phase current balance at mass production.
Other features include overvoltage protection, undervoltage protection and internal softstart. The RT8800A comes to a VQFN-16L 3x3 package. 

Ordering Info

Note :
Richtek Pb-free and Green products are :
► RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020.
► Suitable for use in SnPb or Pb-free soldering processes.
► 100% matte tin (Sn) plating.
 
Features

• 5V Power Supply Voltage
• 2/3-Phase Power Conversion with Automatic Phase Selection
• Output Voltage Controlled by External Reference Voltage
• Precise Core Voltage Regulation
• Power Stage Thermal Balance by DCR Current Sensing
• Extreme Low-Cost, Lossless Time Sharing Current Sensing
• Internal Soft-Start
• Hiccup Mode Over-Current Protection
• Over-Voltage Protection
• Adjustable Operating Frequency and Typical at 300kHz Per Phase
• Power Good Indication
• Small 16-Lead VQFN Package
• RoHS Compliant and 100% Lead (Pb)-Free  

Application

• Desktop CPU Core Power
• Low Output Voltage, High Power Density DC-DC Converters
• Voltage Regulator Modules

Pin Configurations
(TOP VIEW)

VQFN-16L 3x3

RT8800A应用电路